Liberal Democrat plans to allow MPs to job share could actually set back women's rights rather than enhance them, according to a leading constitutional expert.

It has been reported that Lib Dems plan to submit plans to allow two MPs to represent one constituency in order to lessen the work load and encourage more female candidates to stand for election.

Under the proposals due to be presented to the Lib Dem spring conference next month, two candidates would stand on a joint ticket and voters would choose to vote for them in the same way they would vote for an individual MP.

Of the 56 Lib Dem MPs, only seven are women and Nick Clegg is under pressure to increase the diversity of his parliamentary party.

However Ruth Fox, the director and head of research for the Hansard Society, the Westminster based independent, non-partisan political research think-tank, has questioned the viability of the scheme as well as it's worth.

Writing for The Huffington Post UK on Wednesday, Fox raises concerns that the job share arrangement could actually damage the goal of getting more women into parliament and urged political parties to accept that quotas are the only realistic approach.

"Does one half of the team get their hands on the legislative wheel at Westminster while the other grapples with the constituency social work?" she says.

"If so, unless the job-sharers are both women, it doesn’t take much imagination to foresee the risk that it will be the women who work locally and the men that continue to dominate at Westminster. If so, rather than being a solution to women’s representation in politics, job-sharing could end up reinforcing stereotypes."

"There is a risk that rather than advancing the debate about women in politics the job-share solution proves to be counter-productive, becoming a comfort-blanket for reformers who want more women in politics but who can’t or won’t will the means to secure it through the one tried and tested measure that really works, namely quotas."

She adds: "Job-sharing might deliver modest improvements and is understandably attractive for Lib Dems for whom quotas present a strategic challenge given their problems in defining key target seats. But at best it will likely be a marginal solution to a major problem."

Fox, and expert in how parliament functions, said job sharing would be "completely uncharted territory for Westminster" and asked what would happen if one half of the job share turns out to be a "rebel in disguise whilst the other is a party loyalist to the core".

"No candidates could adopt a deal before an election which binds them for all future votes without knowing what those issues and votes may be about," she says.

"So would both halves of a Lib Dem job-share MP have agreed to support their party’s policy u-turn on tuition fees?"

The Lib Dems would also have to explain what would happen if the prime minister would do with ministerial appointments and what to do if one of the pair steps down, falls ill or has to resign as a result of a scandal.

Fox also warns allowing job sharing could also mean that some parties and places have a bigger voice and presence in parliament than others by dint of both job sharers working in practice for 60% of the time. "Is this democratically acceptable; the price we pay for innovative change?" she asks.